Variable area nozzle



L. E. TELBIZOFF VARIABLE AREA NOZZLE Filed Oct. 12, 1946 Zza/ Nov. 28, 1950 Patented Nov. 28, 1950 "UN 1 TED s TATE-ES PATENT 2,531,896

VARIABLE AREA NOZZLE Louis 'E. 'Telbizofi', Monroe, Mich.

Application 'OetoberlZ, 1946, Serial No. 702,912

( Cl. .i13;8=-45) 6 Claims.

This inventionrelates to a variable area nozzle or fluid passagecontrol valve. The invention is particularly useful in controlling the flow "of steam, gas,-or other fluid directed again'stthe blades of a turbine-etc. y In the operation of turbines by steam 'or other fluid, it is common practice today to employ nozzles fixed around the periphery of the entrance tothe turbine in'such a way that the fluid upon leaving the nozzlesfstrikes the first row of blades. Thenozzlesare-all of'the same size and donot "varyin area. The throat-and exit areas or thenozzles afterinstallation remain fixed.

The '"noz'zles are-designed initially to give the correct amount of steam entering the-turbine to give the maximum desired-power, say, 500 kilowatts. V

In the operation of the above structure, should it be desired or necessary toreduce the power output of theturbine, it isnecessary-to cutoff some 'ofthe nozzles and allow less'steam to-strike the blades. This is a very inefiicient process for a number of reasons. 'The use of a reducednumher or nozzles results' in the reduction of the' efiective working-area of the blades-and an-ineflicient utilization of'the'energy of the fluid. Actually when the load becomes-less, the-areas of the nozzles should change to allow less steam to enter and to maintain the highest efiiciency at that load.

In'such-a structure employing steam, gas, or other flu'id, there isfound to be a certain r'nost eihcient-throat area and exit area which a nozzle should have. "These desired areas can be readily calculated. For a difierent load-there should be 'a difierent throat and exitarea for most efficient operation. The ratio that should exist between.

the throat and exit area-does not vary in-direct -proportion as-thechangeofload, and for this reason the exit area should be varied to a di'fier- 'ent extent than the=throat area.

An objeot of the-present invention is to provide a nozzle which is" adjustable as to its throatand exit areas topr'ovidea relatively wide range or such adjustment areas. Yet another object is'to provide a nozzlestructure in which the throat and exit'areas can be regulated so that a correct ratio exists between the throat :and exit areas ancl cor'responding to the different loads encountered. A further object is to provide-a fluid passage controlled by asegmental valve body, with meanswhere'by one portion of .the body may be adjusted withrespect to the other so that the area of thenozzle portionmay be varied'with respect to the" area in the remaining portion 'or .2 the area of the entrance portion. Yet another object to provide 'in a fiui'd massage, a waive slidably mounted therein and having segmental parts in combination *with adjustment mechawherebyone art of the' valve body maysibe moved relative to the other while at ithe isame timeqirovidin -m'eans' iormoving thevalve body as a wholef said assage. Gther spiecificidbjects and advantages 'will appear as' the speoification proceeds.

The invention is illustrated, in aprferreil embodiment, by the accompanying urawing, -Which'- --F-igure 1- a brokenplan-viewofi a turb'iner an 'd a variable area nozzle strueture communicatirig therewith-and embodying my'invention; Fig. 2, a broken enlarged vertical sectional view, tthe section' bein-g taken as indicated '-at line i*2--2 of -Fig. 1 Fig. a perspective view of' the regulator or main valve-body and-Rig. 4, a perspeotivaview of the compensator portion of -'the=valve .lbody.

In the illustration given, .10 designates a turbine casing and II 'theblades of the turbine therein. Communicating with thevcasi-ngi'low and at an anglethereto is a casing I2-providingaflow passage l3-and a-ivalve chamberM-above thefiow passage. Secured in the-casing l2 -i s--. -the .entrance -packing15 urged byrsprings l6 inwardly. Similarly, exit packing l-1 is employed, tnrged 'aby springs l8.

Mountedin the valve chamber- M is-a valve .body I 9 comp ising a regulator: -body; -por, tion .20 and a compensator portion 21. The portions 20 and 2| are hingedly connected-together-at The valve body 19 ,provides a throat portion-.123 in the passage and an-exit portion.

Any suitable .means for adjusting the cvalve .body l9 or the separate components-ifl and-,2! may beemployed. :In the illustration.;;given,";.I provide a topz plate- 25 which isssuspended-above the casing 12 by means of the spring bellows casing 26. PostsZl connect the plateflfi toa the regulator'- valve i-body 2,0, as shown --more clearly in Fig. 12. An adjustment shaft-28 -is;-provi dd withia camiB-adapted toibear-iagainstthe. plate 25 and thus move the member 28 and thereby the compensator-member "2| upwardly and-idown- .wardly.

.In order to move theflmember2O independently of the-remainingstructure .'l9,s:I'3;pifovide.

means as follows. The =member 20-is provided with-awedge opening .39, asshown moreclearly in Fig. 3, and with a verticatepassageiiilzoommuni'cating 'iwithsa. scentral chamber 232. i-The chamberrisz communicates With thG=W-G1E6 P?7 ass 1,896

3 sage 30. A wedge block 33 is mounted in the chamber 30 and extends forwardly into chamber 32. It is urged in a forward direction by spring 34. A second spring 31 within chamber 32 tends to draw the wedge 33 in a forward direction.

. Pivotally connected to the forward end of the wedge 33 is a lever 38 equipped at its forward end with a roller 39. The wall of the chamber 32 at the forward end thereof is inclined as indicated at 40 so as to guide the roller 39 along an inclined path. Pivotally connected to the lever 38 is a plunger 41 having at its top end a plate 42. The plate 42 is maintained at a spaced distance above the top 2 and in sealed relation therewith by the spring bellows 43. An adjustment shaft 44 is provided with an eccentric 45 for operating the plate 42 and plunger 4L The valve body l9 may be formed of any suitable material, as, for example, steel, plastic, glass, etc., and the thickness of the lower wall 46 of the member is such that it will be spread downwardly under the pressure exerted by wedge 33.

The compensator portion 2! is preferably formed as illustrated more clearly in Fig. 4. The member 2| is provided with an integral vertical wall 41 extending obliquely across the portion 2| and provided at, its top with a recess 48. A second vertical wall member 49 is pivotally connected to the wall 41 by means of the pivotal connector 50. A plate 5! extends across the top of member 49 and is supported above the top and the easing 12 by a bellows casing 52. To adjust the compensator plate 5!, I provide a control shaft =53'fixed to a cam member 54.

The casing I2, top 25, and the spring bellows provide a substantially airtight enclosure which will prevent the leakage of steam or other medium which rises into the chamber l4 above the valve body l9. To prevent the trapping of me- :dium within this area, I provide a vent tube 55.

Operation In the operation of the structure, any medium, :such as, for example, steam, passes from a steam chest or other source through the passage 13 in the direction of the arrows and toward the blades ll of the turbine. When the load changes and it is desired to change the relative area at the throat and exit portions, I make the following adjustments. The shaft 23 may be rotated to give a desired vertical movement of the valve body IS. The adjustment shaft 44 may be rotated to move the plunger 4! upwardly or down- 'wardly. Upward movement of the plunger 4| causes the wedge 33 to be pressed inwardly under the force of spring 34, and this moves the spring floor 46 downwardly, thus decreasing the exit area. Downward movement of the plunger 4| causes the roller 39 and lever 33 to move downwardly and to press the wedge 33 toward the right and against the force of compression spring 34 and tension spring 31. This releases the pressure upon the spring floor portion 56 and it rises to a relatively horizontal position shown.

In order to obtain a fine adjustment for the exit opening, I may independently move the member 2i downwardly or upwardly through rotating shaft 53 and the cam 54 carried thereby. Downward movement of the member 49 and member 2i decreases the area at the exit portion of the nozzle.

It will be noted that the valve structure thus provided permits extremely accurate control of the throat and exit areas of the nozzle passage and by different adjustment mechanisms. The valve body operates not only as a segmental valve, but as a variable valve by reason of spring construction. The wedge is effective in changing the rear portion of the valve body with respect to the forward portion, while at the same time therear portion may be adjusted independently of the spring portion by movement of the compensator 2|. Thus great flexibility is provided, giving a. nicety of adjustment in the control of the relative areas at the throat and exit portions of the nozzle passage.

While I have described, for the purpose of clearness, the invention as employed in connection with the control of steam passing from a steam chest into the blades of a turbine, it will be understood that the structure is useful as a control means in the passage of any fluid medium toward a turbine employed for any purpose. Further, while I have described the embodiment illustrated in great detail, it will be understood that such details may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

a 1. A variable area nozzle comprising a casing providing a fluid passage and a valve chamber communicating with the passage, a segmental valve body slidably mounted in said casing for movement into said passage to vary the area thereof, said body having at least one end portion thereof movable relative to the other portion, means for moving said body as a whole, and means for moving the one end portion of the valve body independently of the other.

2. A variable area nozzle comprising a casing providing a fluid passage and a valve chamber communicating with the passage, a segmental valve body slidably mounted in said chamber and movable into said passage to vary the area thereof, said valve body and easing providing a throat portion and an exit portion in said passage, and means for moving said valve body to control the 1 throat area and means for moving independently one segment of said valve body to control the exit area of said passage.

3. A variable area nozzle comprising a casing providing a fluid passage and a valve chamber communicating with the passage, a valve body in said chamber and vertically slidable therein to control the area of said flow passage, said valve body being divided at one end, means for moving said valve body as a whole, and means for spreading said valve body and said divided end to cause the latter portion of said valve body to move vertically relative to the other and thus vary the cross sectional area of the passage at one point thereof relative to the area at another point thereof.

4. A variable area nozzle'comprising a casing providing a fluid passage and a valve chamber communicating with the passage, a valve body in said chamber and slidable vertically therein to control the area of said flow passage, said valve body being divided at one end, means for moving said valve body as a Whole, and means for spreading said valve body and said divided end to cause the latter portion of said valve body to move vertically relative to the other and thus vary the cross sectional area of the passage at one point thereof relative to the area at another point thereof, said last-mentioned means comprising a wedge and control means for moving said wedge to move a resilient portion at the valve relative to said fluid passage and said main valve body.

5. In a fluid passage, a valve body movable therein to vary the area of the fluid passage, said valve body having a resilient lower portion separated from an upper portion by a wedge opening, a wedge block within said opening, and means for moving said wedge block to move the resilient portion of the valve body therebelow relative to the remaining portion of the valve body.

6. In combination, a casing providing a fluid passage and a valve chamber thereabove, a valve body composed of portions relatively movable with respect to each other and slidably mounted in said chamber, members engaging said relatively movable valve portions and extending through said casing, flexible means sealing said members with respect to said casing to prevent the escape of fluid, and means engaging said members for adjusting the relative position of 20 the valve body portions within said casing so The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 352,732 Byrue Nov. 16, 1886 525,002 Buckminster Aug. 28, 1894 589,422 Curtis Sept. 7, 1897 589,466 Curtis Sept. 7, 1897 1,095,767 Adams May 5, 1914 1,556,328 Hutbhins Oct. 6, 1925 1,852,918 Chanler Apr. 5, 1932 2,424,654 Gamble July 9, 1947 FOREIGN PATENTS Number Country Date 20,536 Great Britain Oct. 9, 1897 

